2,790 research outputs found
Public Health Benefits of End-Use Electrical Energy Efficiency in California: An Exploratory Study
This study assesses for California how increasing end-use electrical energy efficiency from installing residential insulation impacts exposures and disease burden from power-plant pollutant emissions. Installation of fiberglass attic insulation in the nearly 3 million electricity-heated homes throughout California is used as a case study. The pollutants nitrous oxides (NO{sub x}), sulfur dioxide (SO{sub 2}), fine particulate matter (PM2.5), benzo(a)pyrene, benzene, and naphthalene are selected for the assessment. Exposure is characterized separately for rural and urban environments using the CalTOX model, which is a key input to the US Environmental Protection Agency (EPA) Tool for the Reduction and Assessment of Chemicals and other environmental Impacts (TRACI). The output of CalTOX provides for urban and rural populations emissions-to-intake factors, which are expressed as an individual intake fraction (iFi). The typical iFi from power plant emissions are on the order of 10{sup -13} (g intake per g emitted) in urban and rural regions. The cumulative (rural and urban) product of emissions, population, and iFi is combined with toxic effects factors to determine human damage factors (HDFs). HDF are expressed as disability adjusted life years (DALYs) per kilogram pollutant emitted. The HDF approach is applied to the insulation case study. Upgrading existing residential insulation to US Department of Energy (DOE) recommended levels eliminates over the assmned 50-year lifetime of the insulation an estimated 1000 DALYs from power-plant emissions per million tonne (Mt) of insulation installed, mostly from the elimination of PM2.5 emissions. In comparison, the estimated burden from the manufacture of this insulation in DALYs per Mt is roughly four orders of magnitude lower than that avoided
Parametric phenomena of the particle dynamics in a periodic gravitational wave field
We establish exactly solvable models for the motion of neutral particles,
electrically charged point and spin particles (U(1) symmetry), isospin
particles (SU(2) symmetry), and particles with color charges (SU(3) symmetry)
in a gravitational wave background. Special attention is devoted to parametric
effects induced by the gravitational field. In particular, we discuss
parametric instabilities of the particle motion and parametric oscillations of
the vectors of spin, isospin, and color charge.Comment: 26 pages, to be published in J. Math. Phy
On logarithmically optimal exact simulation of max-stable and related random fields on a compact set
Coastal vulnerability of a pinned, soft-cliff coastline. Part I, assessing the natural sensitivity to wave climate
The impact of future sea-level rise on coastal erosion as a result of a changing climate has been studied in detail over the past decade. The potential impact of a changing wave climate on erosion rates, however, is not typically considered. We explore the effect of changing wave climates on a pinned, soft-cliff, sandy coastline, using as an example the Holderness coast of East Yorkshire, UK.
The initial phase of the study concentrates on calibrating a numerical model to recently measured erosion rates for the Holderness coast using an ensemble of geomorphological and shoreface parameters under an observed offshore wave climate. In the main phase of the study, wave climate data are perturbed gradually to assess their impact on coastal morphology. Forward-modelled simulations constrain the nature of the morphological response of the coast to changes in wave climate over the next century. Results indicate that changes to erosion rates over the next century will be spatially and temporally heterogeneous, with a variability of up to ±25% in the erosion rate relative to projections under constant wave climate. The heterogeneity results from the current coastal morphology and the sediment transport dynamics consequent on differing wave climate regimes
Assessing the influence of sea walls on the coastal vulnerability of a pinned, soft-cliff, sandy coastline
Coastal defences have long been employed to halt or slow coastal erosion. Their impact on local sediment flux and ecology has been studied in detail through field studies and numerical simulations. The non-local impact of a modified sediment flux regime on mesoscale erosion and accretion has received less attention. Morphological changes at this scale due to defended structures can be difficult to quantify or identify with field data. Engineering scale numerical models, often applied to assess the design of modern defences on local coastal erosion, tend not to cover large stretches of coast and are rarely applied to assess the impact of older structures. We extend previous work to explore the influences of sea walls on the evolution and morphological sensitivity of a pinned, soft-cliff, sandy coastline under a changing wave climate. The Holderness coast of East Yorkshire, UK, is used as a case study, represented both as a defended example with major sea walls included and a natural example where no sea defences exist.
Using a mesoscale numerical coastal evolution model, stochastic wave climate data are perturbed gradually to assess the sensitivity of the coastal morphology to changing wave climate for both the defended and natural scenarios. Comparative analysis of the simulated output suggests that sea walls in the south of the region have a greater impact on sediment flux due to the increased sediment availability along this part of the coast. Multiple defended structures, including those separated by several kilometres, were found to interact with each other, producing a complex imprint on coastal morphology under a changing wave climate. Although spatially and temporally heterogeneous, sea walls generally slowed coastal recession and accumulated sediment on their up-drift side
Coastal vulnerability of a pinned, soft-cliff coastline. Part II, assessing the influence of sea walls on future morphology
Coastal defences have long been employed to halt or slow coastal erosion, and their impact on local
sediment flux and ecology has been studied in detail through field research and numerical simulation. The nonlocal
impact of a modified sediment flux regime on mesoscale erosion and accretion has received less attention.
Morphological changes at this scale due to defending structures can be difficult to quantify or identify with
field data. Engineering-scale numerical models, often applied to assess the design of modern defences on local
coastal erosion, tend not to cover large stretches of coast and are rarely applied to assess the impact of older
structures. We extend previous work to explore the influences of sea walls on the evolution and morphological
sensitivity of a pinned, soft-cliff, sandy coastline under a changing wave climate. The Holderness coast of East
Yorkshire, UK, is used as a case study to explore model scenarios where the coast is both defended with major
sea walls and allowed to evolve naturally were there are no sea defences.
Using a mesoscale numerical coastal evolution model, observed wave-climate data are perturbed linearly to
assess the sensitivity of the coastal morphology to changing wave climate for both the defended and undefended
scenarios. Comparative analysis of the simulated output suggests that sea walls in the south of the region have
a greater impact on sediment flux due to increased sediment availability along this part of the coast. Multiple
defence structures, including those separated by several kilometres, were found to interact with each other,
producing complex changes in coastal morphology under a changing wave climate. Although spatially and
temporally heterogeneous, sea walls generally slowed coastal recession and accumulated sediment on their
up-drift side
Accurate age estimation in small-scale societies
Precise estimation of age is essential in evolutionary anthropology, especially to infer population age structures and understand the evolution of human life history diversity. However, in small-scale societies, such as hunter-gatherer populations, time is often not referred to in calendar years, and accurate age estimation remains a challenge. We address this issue by proposing a Bayesian approach that accounts for age uncertainty inherent to fieldwork data. We developed a Gibbs sampling Markov chain Monte Carlo algorithm that produces posterior distributions of ages for each individual, based on a ranking order of individuals from youngest to oldest and age ranges for each individual. We first validate our method on 65 Agta foragers from the Philippines with known ages, and show that our method generates age estimations that are superior to previously published regression-based approaches. We then use data on 587 Agta collected during recent fieldwork to demonstrate how multiple partial age ranks coming from multiple camps of hunter-gatherers can be integrated. Finally, we exemplify how the distributions generated by our method can be used to estimate important demographic parameters in small-scale societies: here, age-specific fertility patterns. Our flexible Bayesian approach will be especially useful to improve cross-cultural life history datasets for small-scale societies for which reliable age records are difficult to acquire
Deconfined criticality, runaway flow in the two-component scalar electrodynamics and weak first-order superfluid-solid transitions
We perform a comparative Monte Carlo study of the easy-plane deconfined
critical point (DCP) action and its short-range counterpart to reveal close
similarities between the two models for intermediate and strong coupling
regimes. For weak coupling, the structure of the phase diagram depends on the
interaction range: while the short-range model features a tricritical point and
a continuous U(1)xU(1) transition,the long-range DCP action is characterized by
the runaway renormalization flow of coupling into a first (I) order phase
transition. We develop a "numerical flowgram" method for high precision studies
of the runaway effect, weakly I-order transitions, and polycritical points. We
prove that the easy-plane DCP action is the field theory of a weakly I-order
phase transition between the valence bond solid and the easy-plane
antiferromagnet (or superfluid, in particle language) for any value of the weak
coupling strength. Our analysis also solves the long standing problem of what
is the ultimate fate of the runaway flow to strong coupling in the theory of
scalar electrodynamics in three dimensions with U(1)xU(1) symmetry of quartic
interactionsComment: 25 pages, 18 figures, Mottness and quantum criticality conference (to
appear in Annals of physics
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